Revert #1371. Alpha affects only fill.

Fixes #1523

Author: hadley

NEWS.md

@@ -1,5 +1,8 @@
 # ggplot2 2.0.0.9000
 
+* For geoms with both `colour` and `fill`, `alpha` once again only affects
+  fill (Reverts #1371, #1523). This was causing problems for people.
+
 * `geom_path()` knows that "solid" (not just 1) represents a solid line (#1534).
 
 * `layer()` now automatically adds a `na.rm` parameter if none is explicitly

R/geom-polygon.r

@@ -91,7 +91,7 @@ GeomPolygon <- ggproto("GeomPolygon", Geom,
       polygonGrob(munched$x, munched$y, default.units = "native",
         id = munched$group,
         gp = gpar(
-          col = alpha(first_rows$colour, first_rows$alpha),
+          col = first_rows$colour,
           fill = alpha(first_rows$fill, first_rows$alpha),
           lwd = first_rows$size * .pt,
           lty = first_rows$linetype

R/geom-rect.r

@@ -55,7 +55,7 @@ GeomRect <- ggproto("GeomRect", Geom,
         default.units = "native",
         just = c("left", "top"),
         gp = gpar(
-          col = alpha(coords$colour, coords$alpha),
+          col = coords$colour,
           fill = alpha(coords$fill, coords$alpha),
           lwd = coords$size * .pt,
           lty = coords$linetype,

R/geom-ribbon.r

@@ -96,7 +96,7 @@ GeomRibbon <- ggproto("GeomRibbon", Geom,
       default.units = "native",
       gp = gpar(
         fill = alpha(aes$fill, aes$alpha),
-        col = alpha(aes$colour, aes$alpha),
+        col = aes$colour,
         lwd = aes$size * .pt,
         lty = aes$linetype)
     ))

tests/testthat/test-aes-setting.r

@@ -15,3 +15,22 @@ test_that("Aesthetic parameters must match length of data", {
   set_colours(rep("red", 5))
 
 })
+
+test_that("alpha affects only fill colour of solid geoms", {
+  df <- data.frame(x = 1:2, y = 1)
+
+  poly <- ggplot(df, aes(x = x, y)) +
+    geom_polygon(fill = "red", colour = "red", alpha = 0.5)
+  rect <- ggplot(df, aes(xmin = x, xmax = x + 1, ymin = 1, ymax = y + 1)) +
+    geom_rect(fill = "red", colour = "red", alpha = 0.5)
+  ribb <- ggplot(df, aes(x = x, ymin = 1, ymax = y + 1)) +
+    geom_ribbon(fill = "red", colour = "red", alpha = 0.5)
+
+  expect_equal(layer_grob(poly)[[1]]$gp$col[[1]], "red")
+  expect_equal(layer_grob(rect)[[1]]$gp$col[[1]], "red")
+  expect_equal(layer_grob(ribb)[[1]]$children[[1]]$gp$col[[1]], "red")
+
+  expect_equal(layer_grob(poly)[[1]]$gp$fill[[1]], "#FF000080")
+  expect_equal(layer_grob(rect)[[1]]$gp$fill[[1]], "#FF000080")
+  expect_equal(layer_grob(ribb)[[1]]$children[[1]]$gp$fill[[1]], "#FF000080")
+})